Greenhouses or solariums are being used in increasing frequency for home improvement as the ideal solution for adding space and developing an outdoor feeling at relatively low cost and with minimum effort. These greenhouses or solariums (these terms may be used interchangeably herein) are glass enclosures wherein glazing may be supported on frameworks consisting, for example, of lattices or the like fabricated of aluminum extrusions or bars developed to provide for various ancillary functions. These functions and the associated features which permit them to be realized include shading tracks to provide for the raising and lowering of shades, the interconnection of multiple bars, the accomodation of glazing panels with thermal breaks, "weeping" designs to avoid the accumulation of excess moisture, the attaching of internal and external auxiliary members, and the like.
Since the design of the aforesaid extrusions is intended to incorporate so many features and provide for so many functions, the resulting extrusions are often complex. As will be discussed below, they sometimes have exterior and interior halves or parts which are not positionally interchangeable even though they may be symmetrical about a given longitudinal plane.
The aforesaid design characteristic is significant in the erecting of frameworks of particular types. For example, certain lean-to type greenhouses have frameworks which terminate in lefthand and righthand gable ends between which extend a vertical front having a sloped eave which slopes downwardly away from a supporting structure such as a dwelling. The sloped eave will include sloped glazing bars which lie generally in the planes of the gable ends wherein they are supported atop vertical glazing bars.
If, in the above structure, the vertical glazing bars and the sloped glazing bars are to fit snugly together, it is necessary to mitre or slope the top ends of the vertical bars so that the bottom surfaces of the sloped glazing bars can rest flatly against the same. Brief consideration of this arrangement will lead to the realization that different mitres will have to be used for vertical bars in the lefthand and righthand gable ends respectively, unless the vertical bars are completely symmetrical in cross-section.
In most cases, however, the vertical glazing bars are are not completely symmetrical. They have exterior and interior portions which always must face the exterior and interior of the associated greenhouse enclosure whether they are in the lefthand or righthand gable end. This means that a different or reversed mitre must be provided for the lefthand end than for the righthand end for, if the same mitre were to be provided for the tops of all end vertical bars, the mitre would be correct for one end and reversed or improper for the other end. This is due to the fact that the vertical bars in the opposite gable ends have to be mounted in mirror image (i.e., rotated one hundred and eighty degrees) with respect to one another to maintain the proper interior-exterior alignment.
In actual construction, this leads to a problem. It means that two sets of vertical bars have to be made. One set is mitred for the lefthand gable end and the other set is mitred for the righthand gable end. This turn means that it is necessary to manufacture and inventory two separate kinds of gable-end vertical bars with respectively opposite mitres and leads to other complications as well. For example, if the oppositely mitred bars are accidentally mounted in the wrong gable ends, the structure has to be dismantled and reassembled. The problems are all the more accentuated when the greenhouses or solariums are shipped in dismantled form as "do-it-yourself" kits. The problems also include increased manufacturing costs.